Low‐Temperature and Highly Efficient Reduction of O₂‐Containing CO₂ Mixtures via Pt‐Ni/CeO₂ Oxygen Carriers

Abstract

Poor O2 tolerance and high reaction temperature of the conventional oxygen carriers challenge the direct utilization of impure CO2 via chemical looping. Here, Pt‐Ni bimetallic Ce‐based oxygen carriers with excellent O2 tolerance are developed for highly efficient reduction of O2‐containing CO2 at low temperatures. At a temperature as low as 700 °C, high CO2 conversion (≈92%) is obtained over 0.1 wt% Pt‐0.1wt% Ni/CeO2 oxygen carrier in the CO2 feed gas with 16.7% O2 impurities. These results benefit from that Pt‐Ni bimetal plays a crucial role in improving CH4 partial oxidation and accelerating the breaking of the C═O bond to alleviate the competitive oxidation of O2 impurities. Ni compensates for the reduction of low‐temperature redox activity caused by the decrease of Pt content. Moreover, Pt‐Ni/CeO2 oxygen carriers exhibit excellent structural and performance stability during redox cycles. This work presents a feasible strategy for the direct utilization of impure CO2 at low temperatures and realizing a carbon‐neutral cycle.